1. Field of the Invention
This invention relates generally to combustion products of mixed fluid power plants and more specifically to rotating fuel slingers of fuel injection devices for combustion products generators.
2. Description of the Prior Art
Annular combustion chambers are light, inexpensive to manufacture and efficient. In using annular combustion chambers, it is necessary, in order to avoid hot spots which shorten combustion life and cold spots which promote the growth of deposits, to inject fuel uniformly around the chamber.
Uniform fuel injection can be accomplished by using known centrifugal fuel injection systems. One such known centrifugal fuel injection system is illustrated in U.S. Letters Pat. Application Ser. No. 214,703 assigned to the assignee of the present application. That fuel injection system comprises an axially extending circular wall in the shaft assembly of the engine which terminates at a number of radially extending injection passages that project into an annular combustion chamber. The circular wall and passages are an integral part of the rotating compressor-turbine shaft. Centrifugal force causes the fuel to spread out in a layer on the circular wall and flow into the passages. The fuel acquires the tangential velocity of the wall's periphery and is thrown off into the combustion chamber with this velocity. Experience has shown that with such a fuel injection system the hole-to-hole distribution of the fuel is determined by the precision of manufacture of the internal surfaces of the circular wall. Bending of the shaft during rotation will result in eccentricity of the circular wall about the neutral axis causing the layer of fuel to become nonuniform with a fuel buildup along one portion of the circular wall and the thinning out of the fuel along the opposite portion of the circular wall. The nonuniform fuel layer will result in uneven fuel distributing through the passages and can result, in extreme conditions, in the stoppage of flow through some of the passages. When flow is stopped through some of the passages, the feeding passages provide fuel, at any instance, to only a portion of the combustion chamber. This instantaneous partial fuel feeding along with shaft rotation results in the rotation of a flame body around the combustion chamber that is synchronized with shaft speed. Besides reducing combustion chamber efficiency, the rotating flame body condition can also introduce undesirable noise to the operation of the engine. Further, the fuel injection system is relatively expensive to manufacture. Other fuel injection systems that operate in a similar manner are illustrated in U.S. Letters Pat. No. 2,416,389; 2,547,959 and 2,938,345 and French Pat. No. 1,284,281.
Another well known centrifugal fuel injection system, an example of which is illustrated in U.S. Letters Pat. No. 2,659,196, comprises a rotating annular member having radially oriented passages communicating with the combustion chamber and an inner annular reservoir. Fuel is fed to the reservoir by a plurality of fuel delivery tubes that are stationary relative to the engine's housing. Fuel from each delivery tube is projected radially outwardly into the annular reservoir and then through the radially extending passages into the combustion chamber. The centrifugal force causes the fuel to be rapidly ejected through each of the passages over only a small angular portion of each revolution. With such an arrangement it is necessary to use a number of delivery tubes to ensure uniform circumferential fuel injection into the annular combustion chamber.